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Discussion Starter #1
Anyone have issues before with truck stalling for no reason? I have a '15 LML, fuel filter is good, still 90%, oil was changed only a month ago. Truck runs and idles fine but occasionally if I brake hard or make a turn or hit a bump it cuts out. Neutral and restart it with no issues. It doesn't seem like fuel issue, seems like loose wire/connection somewhere. No lights, or codes. Any help appreciated.
 

LHN...We ARE the Joneses
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I've seen threads on it.....can't remember the remedy though, sry.
 

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I've seen threads on it.....can't remember the remedy though, sry.
Anyone have issues before with truck stalling for no reason? I have a '15 LML, fuel filter is good, still 90%, oil was changed only a month ago. Truck runs and idles fine but occasionally if I brake hard or make a turn or hit a bump it cuts out. Neutral and restart it with no issues. It doesn't seem like fuel issue, seems like loose wire/connection somewhere. No lights, or codes. Any help appreciated.
One thing to check, on my 2012 was rubbing of wire harness at the alternator.
 

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Discussion Starter #4
Aright, trying to bump this up and see if anyone else knows anything about this problem. Just happened to me 4 times in about 10 minutes. Truck starts right back up still rolling in neutral so doesn't seem like a fuel issue....have checked all harnesses I can find...no luck...it only seems to do it after warm/hot and after pulling work trailer, and when slowing down for turns...please help!!!!
 

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As always with electrical problems, start with the basics. Check battery for proper voltage. If OK, load check each battery independently. Then start with the positive cables attached to the batteries, both ends, Alternator cable both ends, and the ground cables both ends. Don't just look at them remove them and brush cables and terminals and ground locations until shiney. Same for the mega amp fuses and its cable connections, and the connection of the battery cable to the fuse box. Once you have done this, and you still have problems, start by shaking all the wiring harnesses and connectors, especially to the ECM and TCM and see if you can replicate the problem. It sure sounds like you are either loosing battery or ground somewhere, or critical engine connections.

I had a Mustang years ago that, although only a couple of years old, had a batttery that would short internally and the engine would just die. I'd coast to a stop. Start the engine, and drive on until it happened again. Took quite a while to figure out what the problem was. I should have done the basics the first time it happened and I likely would have fixed my problem much sooner.
 

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Discussion Starter #6
I'm starting to think it's definitely electrical. It seems to be triggered when pulling old work trailer. When I plug in the 4 prong light harness it messes with the brake feeling, and keeps stalling out. Had a service brake system light about 8 months ago for a day then it went away and never had any other issues. Weird though cause the trailer doesn't have electric brakes.
 

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Discussion Starter #7
Aright well gonna follow up for anyone else who may have/develop issues.
So bit the bullet and brought it into the "stealership". Initially they tell me that a main harness along the body/frame is rubbing and has caused a short in wires. They said it is due to the 5.5" lift even though it is a suspension lift and they said the harness comes down from motor/main Computer to trans so there was no changes in clearance there with the lift. Then they called back and said there is a leak on one of the fuel rails/injectors and that is what's causing it. Seems like they are throwing darts at the board. At least injectors/rails getting replaced under factory warranty.
Regarding the trailer issue I was having, I have seen some threads saying that you cannot plug lights in while truck is running. Have to shut the truck off, plug in, then start so the computer can recognize the trailer connection and adjust properly. Hopefully if I can help anyone else in the future.
 

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I can't say I've have ever had any issues with plugging/unplugging the trailers on my truck with the truck running.

I have had to clean the truck side of the 7 pin plug connector on the back of the bumper though due to corrosion.
 

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I have an OPT7 LED Sequential Tailgate Light Bar that plugs straight into the 4 prong harness. But, for some reason every time i put it in R, and hit the brakes, sometimes the light will go crazy and ac like my Hazard Lights are on for a split second. (IMO) could this be due to the Relay in the 3rd brake light? My 3rd brake light does this 3-4 quick blinks, then goes solid. But, i was unsure if anyone else has had issues with the truck, acting completely different when using a PNP(Plug-N-Play) harness vs Hardwiring! Thanks
 

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Discussion Starter #10
Aright, well thought I would do a little follow-up to my original post. After 3 weeks of my truck being at the dealership being "repaired" I finally got it back last Wednesday only to have the truck stall again on me the day after. The dealership said that the right fuel rail was losing pressure and they replaced that saying that would solve the problem. Obviously....they were wrong. So now it's back at the dealership again. I have lost all faith in this dealer service center and don't intend them to ever solve the problem. Gonna start throwing solutions at it myself when I get it back. Gonna start with CAT filter head unit and either a Fass of AD 90 to help out the CP4. Hope no one else is dealing with this cause it sure has become a nightmare.
 

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Discussion Starter #11
Aright, final post from me with the end result. After 4 weeks at the dealership and tearing it apart twice, 2 new fuel rails, replaced 2 injectors, it ended up being the fuel pressure regulator on the side of the CP4. Funny thing was is I suggested that to them 4 weeks ago when it first went in with the stalling problem. Of course I got the shrug off and the "what does he know" from mechanic/service writer. I suppose I shouldn't complain to much considering .everything was covered under manufacturers warranty and other than the injectors and actual pump I have a totally new fuel system. Hope this can help someone else in future.
 

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Glad problem solved. Thanks for posting solution.
 
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